plyr v1.8.4

Tools for Splitting, Applying and Combining Data

A set of tools that solves a common set of problems: you need to break a big problem down into manageable pieces, operate on each piece and then put all the pieces back together. For example, you might want to fit a model to each spatial location or time point in your study, summarise data by panels or collapse high-dimensional arrays to simpler summary statistics. The development of 'plyr' has been generously supported by 'Becton Dickinson'.

Readme

plyr

plyr is a set of tools for a common set of problems: you need to split up a big data structure into homogeneous pieces, apply a function to each piece and then combine all the results back together. For example, you might want to:

fit the same model each patient subsets of a data frame
quickly calculate summary statistics for each group
perform group-wise transformations like scaling or standardising

It's already possible to do this with base R functions (like split and the apply family of functions), but plyr makes it all a bit easier with:

totally consistent names, arguments and outputs
convenient parallelisation through the foreach package
input from and output to data.frames, matrices and lists
progress bars to keep track of long running operations
built-in error recovery, and informative error messages
labels that are maintained across all transformations

Considerable effort has been put into making plyr fast and memory efficient, and in many cases plyr is as fast as, or faster than, the built-in equivalents.

A detailed introduction to plyr has been published in JSS: "The Split-Apply-Combine Strategy for Data Analysis", http://www.jstatsoft.org/v40/i01/. You can find out more at http://had.co.nz/plyr/, or track development at http://github.com/hadley/plyr. You can ask questions about plyr (and data manipulation in general) on the plyr mailing list. Sign up at http://groups.google.com/group/manipulatr.

Functions in plyr

Name	Description
as.data.frame.function	Make a function return a data frame.
arrange	Order a data frame by its colums.
a_ply	Split array, apply function, and discard results.
amv_dimnames	Dimension names.
as.quoted	Convert input to quoted variables.
alply	Split array, apply function, and return results in a list.
amv_dim	Dimensions.
aaply	Split array, apply function, and return results in an array.
adply	Split array, apply function, and return results in a data frame.
as.list.split	Convert split list to regular list.
ddply	Split data frame, apply function, and return results in a data frame.
defaults	Set defaults.
d_ply	Split data frame, apply function, and discard results.
create_progress_bar	Create progress bar.
eval.quoted	Evaluate a quoted list of variables.
here	Capture current evaluation context.
empty	Check if a data frame is empty.
dlply	Split data frame, apply function, and return results in a list.
dims	Number of dimensions.
id	Compute a unique numeric id for each unique row in a data frame.
is.formula	Is a formula? Checks if argument is a formula
idata.frame	Construct an immutable data frame.
count	Count the number of occurences.
join_all	Recursively join a list of data frames.
l_ply	Split list, apply function, and discard results.
join.keys	Join keys. Given two data frames, create a unique key for each row.
desc	Descending order.
baseball	Yearly batting records for all major league baseball players
indexed_df	An indexed data frame.
indexed_array	An indexed array.
colwise	Column-wise function.
compact	Compact list.
join	Join two data frames together.
daply	Split data frame, apply function, and return results in an array.
liply	Experimental iterator based version of llply.
laply	Split list, apply function, and return results in an array.
m_ply	Call function with arguments in array or data frame, discarding results.
list_to_vector	List to vector.
list_to_array	List to array.
[.split	Subset splits.
mapvalues	Replace specified values with new values, in a vector or factor.
mutate	Mutate a data frame by adding new or replacing existing columns.
name_rows	Toggle row names between explicit and implicit.
match_df	Extract matching rows of a data frame.
names.quoted	Compute names of quoted variables.
plyr-deprecated	Deprecated Functions in Package plyr
mdply	Call function with arguments in array or data frame, returning a data frame.
ozone	Monthly ozone measurements over Central America.
nunique	Number of unique values.
id_var	Numeric id for a vector.
.	Quote variables to create a list of unevaluated expressions for later evaluation.
progress_win	Graphical progress bar, powered by Windows.
each	Aggregate multiple functions into a single function.
quickdf	Quick data frame.
failwith	Fail with specified value.
progress_none	Null progress bar
print.split	Print split.
rbind.fill	Combine data.frames by row, filling in missing columns.
raply	Replicate expression and return results in a array.
plyr	plyr: the split-apply-combine paradigm for R.
print.quoted	Print quoted variables.
rename	Modify names by name, not position.
revalue	Replace specified values with new values, in a factor or character vector.
round_any	Round to multiple of any number.
splitter_a	Split an array by .margins.
take	Take a subset along an arbitrary dimension
vaggregate	Vector aggregate.
summarise	Summarise a data frame.
try_default	Try, with default in case of error.
rdply	Replicate expression and return results in a data frame.
rbind.fill.matrix	Bind matrices by row, and fill missing columns with NA.
reduce_dim	Reduce dimensions.
tryapply	Apply with built in try. Uses compact, lapply and tryNULL
split_labels	Generate labels for split data frame.
unrowname	Un-rowname.
is.discrete	Determine if a vector is discrete.
loop_apply	Loop apply
isplit2	Split iterator that returns values, not indices.
maply	Call function with arguments in array or data frame, returning an array.
llply	Split list, apply function, and return results in a list.
ldply	Split list, apply function, and return results in a data frame.
list_to_dataframe	List to data frame.
mlply	Call function with arguments in array or data frame, returning a list.
progress_tk	Graphical progress bar, powered by Tk.
progress_text	Text progress bar.
progress_time	Text progress bar with time.
rlply	Replicate expression and return results in a list.
r_ply	Replicate expression and discard results.
true	Function that always returns true.
splat	`Splat' arguments to a function.
split_indices	Split indices.
splitter_d	Split a data frame by variables.
strip_splits	Remove splitting variables from a data frame.
No Results!

Name

Description

as.data.frame.function

Make a function return a data frame.

arrange

Order a data frame by its colums.

a_ply

Split array, apply function, and discard results.

amv_dimnames

Dimension names.

as.quoted

Convert input to quoted variables.

alply

Split array, apply function, and return results in a list.

amv_dim

Dimensions.

aaply

Split array, apply function, and return results in an array.

adply

Split array, apply function, and return results in a data frame.

as.list.split

Convert split list to regular list.

ddply

Split data frame, apply function, and return results in a data frame.

defaults

Set defaults.

d_ply

Split data frame, apply function, and discard results.

create_progress_bar

Create progress bar.

eval.quoted

Evaluate a quoted list of variables.

here

Capture current evaluation context.

empty

Check if a data frame is empty.

dlply

Split data frame, apply function, and return results in a list.

dims

Number of dimensions.

Compute a unique numeric id for each unique row in a data frame.

is.formula

Is a formula? Checks if argument is a formula

idata.frame

Construct an immutable data frame.

count

Count the number of occurences.

join_all

Recursively join a list of data frames.

l_ply

Split list, apply function, and discard results.

join.keys

Join keys. Given two data frames, create a unique key for each row.

desc

Descending order.

baseball

Yearly batting records for all major league baseball players

indexed_df

An indexed data frame.

indexed_array

An indexed array.

colwise

Column-wise function.

compact

Compact list.

join

Join two data frames together.

daply

Split data frame, apply function, and return results in an array.

liply

Experimental iterator based version of llply.

laply

Split list, apply function, and return results in an array.

m_ply

Call function with arguments in array or data frame, discarding results.

List to vector.

List to array.

Subset splits.

Replace specified values with new values, in a vector or factor.

mutate

Mutate a data frame by adding new or replacing existing columns.

name_rows

Toggle row names between explicit and implicit.

match_df

Extract matching rows of a data frame.

names.quoted

Compute names of quoted variables.

plyr-deprecated

Deprecated Functions in Package plyr

mdply

Call function with arguments in array or data frame, returning a data frame.

ozone

Monthly ozone measurements over Central America.

nunique

Number of unique values.

id_var

Numeric id for a vector.

Quote variables to create a list of unevaluated expressions for later evaluation.

progress_win

Graphical progress bar, powered by Windows.

each

Aggregate multiple functions into a single function.

quickdf

Quick data frame.

failwith

Fail with specified value.

progress_none

Null progress bar

print.split

Print split.

rbind.fill

Combine data.frames by row, filling in missing columns.

raply

Replicate expression and return results in a array.

plyr

plyr: the split-apply-combine paradigm for R.

print.quoted

Print quoted variables.

rename

Modify names by name, not position.

revalue

Replace specified values with new values, in a factor or character vector.

round_any

Round to multiple of any number.

splitter_a

Split an array by .margins.

take

Take a subset along an arbitrary dimension

vaggregate

Vector aggregate.

summarise

Summarise a data frame.

try_default

Try, with default in case of error.

rdply

Replicate expression and return results in a data frame.

rbind.fill.matrix

Bind matrices by row, and fill missing columns with NA.

reduce_dim

Reduce dimensions.

tryapply

Apply with built in try. Uses compact, lapply and tryNULL

split_labels

Generate labels for split data frame.

unrowname

Un-rowname.

is.discrete

Determine if a vector is discrete.

loop_apply

Loop apply

isplit2

Split iterator that returns values, not indices.

maply

Call function with arguments in array or data frame, returning an array.

llply

Split list, apply function, and return results in a list.

ldply

Split list, apply function, and return results in a data frame.

list_to_dataframe

List to data frame.

mlply

Call function with arguments in array or data frame, returning a list.

progress_tk

Graphical progress bar, powered by Tk.

progress_text

Text progress bar.

progress_time

Text progress bar with time.

rlply

Replicate expression and return results in a list.

r_ply

Replicate expression and discard results.

true

Function that always returns true.

splat

`Splat' arguments to a function.

split_indices

Split indices.

splitter_d

Split a data frame by variables.

strip_splits

Remove splitting variables from a data frame.

No Results!

Details

URL	http://had.co.nz/plyr, https://github.com/hadley/plyr
BugReports	https://github.com/hadley/plyr/issues
LinkingTo	Rcpp
License	MIT + file LICENSE
LazyData	true
RoxygenNote	5.0.1
NeedsCompilation	yes
Packaged	2016-06-07 19:58:36 UTC; hadley
Repository	CRAN
Date/Publication	2016-06-08 10:40:15

suggests	abind , covr , doParallel , foreach , iterators , itertools , tcltk , testthat
depends	R (>= 3.1.0)
imports	Rcpp (>= 0.11.0)
Contributors

plyr v1.8.4

Tools for Splitting, Applying and Combining Data

Readme

plyr

Functions in plyr

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